actual billing not showing up for one of my projects and math is incorrect on others....help

Hi all - looking for suggestions please. I have one project that will not show billing info. under the "project management" tab ....sub tab "projects"...column "billing" my other projects summarize under this heading but for some reason on project won't. I compared billing rates and they are set the same, my hours come up properly as do the costs, I just cant get the billing section active. Also the math is out on the billing figures for all the other projects it should be hours x $120.00 but it is coming out to hours x $160.00 I've searching the forum's help section for a few hours with no headway, any thoughts on where to try next? thanks in advance for your help.